ᐅ How do civil engineers determine the depth for various construction projects?

Attention – silly question ;-)).

Soon, the excavation contractor will start work. Now I have a general question that might be amusing for the professionals:

The surveyor does the rough staking and sets a reference elevation point (e.g., top edge of the finished floor).

How deep the hole needs to be is determined by the basement builder (the above-mentioned reference point minus the thickness of the ground floor slab, minus the thickness of the basement ceiling, minus the room height, minus the thickness of the base slab).

That part is clear to me. Now I’m just wondering, how does the excavation contractor know how deep to dig?

Hm, how does he measure? How else, really? Hehe :-)

That’s clear to me ;-)
But how does he do it? The highest point is a bit away from the excavation pit; otherwise, he might roll over it with the excavator. He somehow has to transfer the elevation of that point into the pit.

With these parts (I don’t know the name) that stand on the tripod you look through. You place it on a well-known height point (in our case a manhole) and the helper walks through the pit holding a rod 🙂

perlenmann schrieb:
With these parts (I don’t know the name) that stand on a tripod and you look through them. You set it on a known height point (for us, a manhole cover) and the helper walks through the excavation with a rod. 🙂

Leveling instrument

Thanks, you too ;-)